U.S. patent application number 15/640281 was filed with the patent office on 2017-10-26 for specializing virtual network device processing to avoid interrupt processing for high packet rate applications.
The applicant listed for this patent is VMware, Inc.. Invention is credited to Jin Heo, Lenin Singaravelu, Ayyappan Veeraiyan, Yong Wang, Jui-Ting Weng.
Application Number | 20170310571 15/640281 |
Document ID | / |
Family ID | 56130776 |
Filed Date | 2017-10-26 |
United States Patent
Application |
20170310571 |
Kind Code |
A1 |
Singaravelu; Lenin ; et
al. |
October 26, 2017 |
SPECIALIZING VIRTUAL NETWORK DEVICE PROCESSING TO AVOID INTERRUPT
PROCESSING FOR HIGH PACKET RATE APPLICATIONS
Abstract
A method of optimizing network processing in a system comprising
a physical host and a set of physical network interface controllers
(PNICs) is provided. The physical host includes a forwarding
element. The method includes determining that a set of conditions
is satisfied to bypass the forwarding element for exchanging
packets between a particular data compute node (DCN) and a
particular PNIC. The set of conditions includes the particular DCN
being the only DCN connected to the forwarding element and the
particular PNIC being the only PNIC connected to the forwarding
element. The method exchanges packets between the particular DCN
and the particular PNIC bypassing the forwarding element. The
method determines that at least one condition in said set of
conditions is not satisfied. The method utilizes the forwarding
element to exchange packets between the particular DCN and the
particular PNIC.
Inventors: |
Singaravelu; Lenin;
(Sunnyvale, CA) ; Heo; Jin; (Mountain View,
CA) ; Weng; Jui-Ting; (Sunnyvale, CA) ;
Veeraiyan; Ayyappan; (Cupertino, CA) ; Wang;
Yong; (Sunnyvale, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
VMware, Inc. |
Palo Alto |
CA |
US |
|
|
Family ID: |
56130776 |
Appl. No.: |
15/640281 |
Filed: |
June 30, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14574354 |
Dec 17, 2014 |
9699060 |
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15640281 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 43/103 20130101;
H04L 47/28 20130101; H04L 43/0894 20130101; G06F 9/45558 20130101;
H04L 43/16 20130101; G06F 2009/45595 20130101 |
International
Class: |
H04L 12/26 20060101
H04L012/26; H04L 12/26 20060101 H04L012/26; H04L 12/26 20060101
H04L012/26; G06F 9/455 20060101 G06F009/455 |
Claims
1. A method of high packet rate network processing in a system
comprising a physical host and a set of physical network interface
controllers (PNICs), the physical host hosting a set of data
compute nodes (DCNs) for each of a set of tenants, each DCN
comprising a virtual network interface controller (VNIC) for
communicating with one or more PNICs to exchange packets, the
method comprising: determining whether a predetermined number of
packets have been received at a VNIC from a particular DNC; when
the predetermined number of packets have been received at the VNIC
from the particular DNC, generate an interrupt to the
virtualization software; and when the predetermined number of
packets have not been received at the VNIC from the particular DNC:
determining a rate of packets received from the particular DCN at
the VNIC; and when the rate of packets exceeds the predetermined
threshold, performing polling to determine the availability of
packets received at the VNIC from the particular DCN; and when the
rate of packets does not exceed the predetermined threshold,
utilizing interrupts to determine the availability of packets
received at the VNIC from the particular DCN.
2. The method of claim 1, wherein the physical host comprises
virtualization software, wherein performing polling to determine
the availability of packets received at the VNIC from the
particular DCN comprises: determining, by the VNIC, that a packet
is received from the particular DCN; storing the packet in a buffer
for the virtualization software to pick up; and updating a number
of packets in the buffer.
3. The method of claim 2, wherein performing polling further
comprises: determining, by the virtualization software, that the
VNIC has to be polled; and determining whether the VNIC has stored
any packets in the buffer.
4. The method of claim 3, further comprising: picking up packets
from the buffer by the virtualization software; and setting the
number of packets in the buffer to zero.
5. The method of claim 4, further comprising starting a timer by
the virtualization software to perform a next poll to determine the
availability of packets received from the particular DCN at the
VNIC.
6. The method of claim 1, wherein the physical host comprises
virtualization software, and wherein the method further comprises
generating an interrupt to the virtualization software to inform
the virtualization software that packets have arrived from the
particular DCN when a predetermined number of packets have arrived
at the VNIC from the particular DCN.
7. The method of claim 1, wherein the physical host comprises
virtualization software, and wherein the method further comprises
generating an interrupt to the virtualization software to inform
the virtualization software that packets have arrived from the
particular DCN when a predetermined number of packets have arrived
at the VNIC from the particular DCN.
8. A non-transitory machine-readable medium storing a program for
of high packet rate network processing in a system comprising a
physical host and a set of physical network interface controllers
(PNICs), the physical host hosting a set of data compute nodes
(DCNs) for each of a set of tenants, each DCN comprising a virtual
network interface controller (VNIC) for communicating with one or
more PNICs to exchange packets, the program executable by at least
one processing unit, the program comprising sets of instructions
for: determining whether a predetermined number of packets have
been received at a VNIC from a particular DNC; when the
predetermined number of packets have been received at the VNIC from
the particular DNC, generate an interrupt to the virtualization
software; and when the predetermined number of packets have not
been received at the VNIC from the particular DNC: determining a
rate of packets received from the particular DCN at the VNIC; and
when the rate of packets exceeds the predetermined threshold,
performing polling to determine the availability of packets
received at the VNIC from the particular DCN; and when the rate of
packets does not exceed the predetermined threshold, utilizing
interrupts to determine the availability of packets received at the
VNIC from the particular DCN.
9. The non-transitory machine-readable medium of claim 8, wherein
the physical host comprises virtualization software, and wherein
the sets of instructions for performing polling to determine the
availability of packets received at the VNIC from the particular
DCN comprises sets of instructions for: determining, by the VNIC,
that a packet is received from the particular DCN; storing the
packet in a buffer for the virtualization software to pick up; and
updating a number of packets in the buffer.
10. The non-transitory machine-readable medium of claim 9, wherein
the sets of instructions for performing polling further comprises
sets of instructions for: determining, by the virtualization
software, that the VNIC has to be polled; and determining whether
the VNIC has stored any packets in the buffer.
11. The non-transitory machine-readable medium of claim 10, wherein
the program further comprises sets of instructions for: picking up
packets from the buffer by the virtualization software; and setting
the number of packets in the buffer to zero.
12. The non-transitory machine-readable medium of claim 11, wherein
the program further comprises sets of instructions for starting a
timer by the virtualization software to perform a next poll to
determine the availability of packets received from the particular
DCN at the VNIC.
13. The non-transitory machine-readable medium of claim 8, wherein
the physical host comprises virtualization software, and wherein
the program further comprises sets of instructions for: utilizing
interrupts to determine an availability of packets received at the
VNIC from the particular DCN; and generating an interrupt to the
virtualization software to inform the virtualization software that
packets have arrived from the particular DCN when a predetermined
number of packets have arrived at the VNIC from the particular
DCN.
14. The non-transitory machine-readable medium of claim 8, wherein
the physical host comprises virtualization software, and wherein
the program further comprises sets of instructions for: utilizing
interrupts to determine the availability of packets received at the
VNIC from the particular DCN; and generating an interrupt to the
virtualization software to inform the virtualization software that
packets have arrived from the particular DCN when the predetermined
number of packets have arrived at the VNIC from the particular
DCN.
15. A physical computing device comprising: a set of processing
units; and a non-transitory machine-readable medium storing a
program for execution by the set of processing units, the physical
computing device hosting a set of data compute nodes (DCNs) for
each of a set of tenants, each DCN comprising a virtual network
interface controller (VNIC) for communicating with one or more
PNICs to exchange packets, the sets of instructions for:
determining whether a predetermined number of packets have been
received at a VNIC from a particular DNC; when the predetermined
number of packets have been received at the VNIC from the
particular DNC, generate an interrupt to the virtualization
software; and when the predetermined number of packets have not
been received at the VNIC from the particular DNC: determining a
rate of packets received from the particular DCN at the VNIC; and
when the rate of packets exceeds the predetermined threshold,
performing polling to determine the availability of packets
received at the VNIC from the particular DCN; and when the rate of
packets does not exceed the predetermined threshold, utilizing
interrupts to determine the availability of packets received at the
VNIC from the particular DCN.
16. The physical computing device of claim 15, wherein the physical
host comprises virtualization software, wherein the set of
instructions for performing polling to determine the availability
of packets received at the VNIC from the particular DCN comprises
sets of instructions for: determining by the VNIC that a packet is
received from the particular DCN; storing the packet in a buffer
for the virtualization software to pick up; and updating a number
of packets in the buffer.
17. The physical computing device of claim 16, wherein the set of
instructions for performing polling further comprises sets of
instructions for: determining, by the virtualization software, that
the VNIC has to be polled; and determining whether the VNIC has
stored any packets in the buffer.
18. The physical computing device of claim 17, wherein the program
further comprises sets of instructions for: picking up packets from
the buffer by the virtualization software; and setting the number
of packets in the buffer to zero.
19. The physical computing device of claim 18, wherein the program
further comprises a set of instructions for starting a timer by the
virtualization software to perform a next poll to determine an
availability of packets received from the particular DCN at the
VNIC.
20. The physical computing device of claim 15, wherein the physical
host comprises virtualization software, and wherein the program
further comprises a set of instructions for; utilizing interrupts
to determine an availability of packets received at the VNIC from
the particular DCN; and generating an interrupt to the
virtualization software to inform the virtualization software that
packets have arrived from the particular DCN when the predetermined
number of packets have arrived at the VNIC from the particular DCN.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 14/574,336, filed Dec. 17, 2014, entitled "Specializing Virtual
Network Device Processing to Bypass Forwarding Elements for High
Packet Rate Applications", the entirety of which is incorporated by
reference.
BACKGROUND
[0002] Virtualization of network devices provides many advantages
in virtualized environments. It allows for sharing a single
physical device amongst multiple virtual machines, setting resource
limits (e.g., CPU for processing, packet rate and throughput limits
for isolation), packet inspection, migration of virtual machines,
and enables many features such as fault-tolerance and high
availability. However, virtualization of network devices also adds
considerable CPU processing overheads. In some cases, workloads
show an overhead of 30% to 200% over a purely non-virtualized
implementation. High packet rate applications such as firewalls,
routers, and Dynamic Host Configuration Protocol (DHCP) servers
require performance in the order of a few million to a few tens of
million packets processed per second and the virtual device
processing overhead limits performance to a million to a few
million packets/sec.
[0003] Single Root IO Virtualization (SR-IOV) is a mix of hardware
and software solutions to support high performance networking
workloads on virtualized environments. SR-IOV allows for
capabilities such as device sharing and moving of virtual machines
between different hosts on some virtualization platforms. However,
SR-IOV requires special hardware and SR-IOV enabled physical
network interface controllers (PNICs) and SR-IOV capable drivers.
Implementing other virtualization features such as memory
over-commit or virtual machine fault-tolerance might require future
hardware and software updates while features such as packet
inspection might not be possible.
BRIEF SUMMARY
[0004] Methods and systems are provided to make packet processing
more efficient for virtual network devices. Typically, a virtual
machine (VM) is connected to a physical network interface
controller (PNIC) through a virtual switch. For instance, the VM is
connected to a port on the virtual switch through a virtual network
interface controller (VNIC). The PNIC is connected to another port
on the virtual switch. The VM sends and receives packets through
the PNIC. Some embodiments identify a virtual machine (VM) that
consumes all traffic on a single physical network interface
controller (PNIC) and is not sharing the PNIC with any other VMs.
These embodiments provide a specialization of the virtual device
processing that bypasses the virtual switch layer and hook up the
virtual device code with the physical code. Since there is a single
source port and a single destination port, any traffic an external
switch routes to the PNIC reaches the VM and vice versa.
[0005] Bypassing the virtual switching layer reduces processing
cost per packet by around 5%-10% and increases the packet
processing ability accordingly. Bypassing of the virtual switch is
a runtime decision. Once a need arises for connecting the VM to the
switch (e.g., when another VM is moved to the same host, port
mirroring is needed to tap the packets, or any services the VM
requires that needs the virtual switch), the VM is switched to use
the virtual switch. The VM is transparently switched between a fast
path (no switching) and slow path (switching) to provide the
required features of virtualization.
[0006] Some embodiments identify applications that consistently
have high packet rates. These embodiments provide a tradeoff
between the processing resources and higher packet rates. These
embodiments modify virtual device processing to occur in polling
mode rather then interrupt (or sys-call) driven mode. Streamlining
virtual device processing provides a two-fold advantage. First,
packet processing does not incur any latency. Second, the virtual
backend, virtual machine monitor, guest kernel, and guest device
driver for the virtual network device do not have to execute
interrupt coalescing and interrupt processing code. The processing
overhead is reduced by 1%-2%, increasing packet processing by a
similar amount. Some embodiments turn on/off the polling mode when
a VNIC is initialized (e.g., at the time of VM boot or VNIC reset).
In other embodiments, the polling mode is adaptively turned on or
off during the runtime. In these embodiments, polling is turned on
when packet rate is high and turns off polling when the packet rate
is low.
[0007] The preceding Summary is intended to serve as a brief
introduction to some embodiments of the invention. It is not meant
to be an introduction or overview of all inventive subject matter
disclosed in this document. The Detailed Description that follows
and the Drawings that are referred to in the Detailed Description
will further describe the embodiments described in the Summary as
well as other embodiments. Accordingly, to understand all the
embodiments described by this document, a full review of the
Summary, Detailed Description and the Drawings is needed. Moreover,
the claimed subject matters are not to be limited by the
illustrative details in the Summary, Detailed Description and the
Drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The novel features of the invention are set forth in the
appended claims. However, for purposes of explanation, several
embodiments of the invention are set forth in the following
figures.
[0009] FIG. 1 conceptually illustrates a virtualized infrastructure
domain in some embodiments of the invention.
[0010] FIG. 2 conceptually illustrates a forwarding element that is
only connected to one VM and one physical NIC.
[0011] FIG. 3 conceptually illustrates the VM of FIG. 2 after the
forwarding element is bypassed in some embodiments of the
invention.
[0012] FIGS. 4A and 4 B conceptually illustrate a process for
determining whether a forwarding element can be bypassed in the
path between a VM and a physical VIC in some embodiments of the
invention.
[0013] FIG. 5 conceptually illustrates SR-IOV virtualization on a
host in some embodiments of the invention.
[0014] FIG. 6 conceptually illustrates SR-IOV virtualization on a
host in some embodiments of the invention where VMs that cannot
bypass virtualization software stack are connected to a single
SRI-OV enabled PNIC.
[0015] FIG. 7 conceptually illustrates SR-IOV virtualization of
FIG. 6 where each VM is connected to a different VF through a
separate forwarding element.
[0016] FIG. 8 conceptually illustrates SR-IOV virtualization on a
host in some embodiments of the invention where a VM that cannot
bypass virtualization software stack bypasses the forwarding
element and connects to a VF through a VNIC.
[0017] FIG. 9 conceptually illustrates a process for determining
whether each VMs on a host can be connected to a VF of an SR-IOV
capable PNIC in some embodiments of the invention.
[0018] FIG. 10 conceptually illustrates a process for determining
whether a forwarding element can be bypassed in the path between a
VM and a VF of an SR-My enabled PNIC in some embodiments of the
invention.
[0019] FIG. 11 conceptually illustrates a process for dynamically
determining whether to use polling or interrupts to send transmit
packets from each of a tenant's VMs to the virtualization software
in some embodiments of the invention.
[0020] FIG. 12 conceptually illustrates a process for performing
interrupt coalescing in some embodiments of the invention.
[0021] FIG. 13 conceptually illustrates a process performed by the
VNIC when the virtualization software performs polling to determine
the availability of VM transmit packets in some embodiments of the
invention.
[0022] FIG. 14 conceptually illustrates a process performed by the
virtualization software in some embodiments to poll a VNIC to
determine whether transmit packets are available from the VM.
[0023] FIG. 15 conceptually illustrates an electronic system with
which some embodiments of the invention are implemented.
DETAILED DESCRIPTION
[0024] In the following detailed description of the invention,
numerous details, examples, and embodiments of the invention are
set forth and described. However, it will be clear and apparent to
one skilled in the art that the invention is not limited to the
embodiments set forth and that the invention may be practiced
without some of the specific details and examples discussed.
[0025] Virtualization is the ability to simulate a hardware
platform, such as a server, storage device or network resource, in
software. A virtual machine (VM) is a software implementation of a
machine such as a computer. FIG. 1 conceptually illustrates a
virtualized infrastructure domain in some embodiments of the
invention. The virtualized infrastructure domain is in some
embodiments a virtualized infrastructure that is managed by a
single cloud management system. The virtualized infrastructure
domain includes a set of host machines 101, one of which is shown
in FIG. 1. Each host can host one or more tenants, each tenant can
have one or more VMs 110 and 170. In FIG. 1, VMs 110 belong to one
tenant and VMs 170 belong to a different tenant. The host machines
also host a set of services that provide different services. The
term cloud service refers to services (such as computing, storage,
etc.) provided in a distributed manner over a network.
[0026] As shown, the host 101 includes virtualization software
(sometimes referred to as a hypervisor) 115. The virtualization
software 115 is representative of the various types of
virtualization software that may operate on hosts in such a
virtualized infrastructure (e.g., virtual machine monitor, etc.).
In some embodiments, this virtualization software 115 includes one
or more forwarding elements 105-107.
[0027] The VMs of each tenant form a logical network (also referred
to as private network or virtual network). The logical network is
identified by a logical network identifier (also known as virtual
network identifier or VNI). Each logical network is configured by a
tenant. The logical network is an abstraction of a physical network
and may provide a virtual Layer 2 (or data link layer) for services
such as encapsulation and decapsulation of network layer data
packets into frames, frame synchronization, medial access control,
etc. The logical network may span one or more physical networks and
be organized independent of the underlying physical topology and
organization of the physical networks.
[0028] In some embodiments, the forwarding element in the
virtualization software is a physical forwarding element (PFE) such
as a virtual switch. In the virtualization field, some refer to
software switches as virtual switches as these are software
elements. However, in this specification, the software forwarding
elements are referred to as physical forwarding elements (PFEs), in
order to distinguish them from logical forwarding elements (LFEs),
which are logical constructs that are not tied to the physical
world. A PFE forwards packets in a physical network whether or not
it is implemented in software while a LFE forwards packets in a
logical network, which is logically decoupled or abstracted from
the physical network. In other words, the software forwarding
elements are referred to as PFEs because they exist and operate in
the physical world, whereas an LFE is a logical representation of a
forwarding element that is presented to a user when designing a
logical network.
[0029] In some embodiments, several PFEs are distributed throughout
the network implement tenant's LFEs, where each PFE is a local
instantiation, or a proxy, of an LFE that operate across different
host machines and can perform L 3 packet forwarding between VMs on
the host machine or on different host machines. An LFE is sometimes
referred to as a virtual distributed switch (VDS). In the following
discussions, the term forwarding element refers to either a PFE or
an LFE, depending on a particular configuration.
[0030] In each host 101, each forwarding elements 105-107 connects
to one or more physical network interface controllers (PNICs) 120
to send outgoing packets and to receive incoming packets through a
physical network 145. As shown, each forwarding element 105-107 in
FIG. 1 is defined to include one or more ports 135 (or a port group
130) through which it connects to uplinks 150 and the physical NICs
120 to send and receive packets.
[0031] Each forwarding element 105-107 is also defined to have a
set of virtual ports 160 (or a virtual port group 140) to connect
to VMs 110 through virtual NICs (VNICs) 125 to the forwarding
element 105. A port group is a group of ports that have the same
configuration. An uplink 150 is a module that relays packets
between the forwarding element 105 and the physical NIC 120 in
order to perform various packet processing functions on incoming
and outgoing traffic.
[0032] I. Selective Bypassing or use of Forwarding Elements
[0033] Some embodiments identify a VM that consumes all traffic on
a single physical network interface controller (PNIC) and is not
sharing the PNIC with any other VMs. These embodiments provide a
specialization of the virtual device processing that bypasses the
virtual switch layer and hook up the virtual device code with the
physical code. Since there is a single source port and a single
destination port, any traffic an external switch routes to the PNIC
reaches the VM and vice versa.
[0034] Bypassing the virtual switching layer reduces processing
cost per packet by around 5%-10% and increases the packet
processing ability accordingly. Bypassing of the virtual switch is
a runtime decision. Once a need arises for connecting the VM to the
switch (e.g., when another VM is moved to the same host, port
mirroring is needed to tap the packets, or any services the VM
requires that needs the virtual switch), the VM is switched to use
the virtual switch. The VM is transparently switched between a fast
path (no switching) and slow path (switching) to provide the
required features of virtualization.
[0035] A. Criteria to Use or Bypass the Forwarding Element
[0036] FIG. 2 conceptually illustrates a forwarding element that is
only connected to one VM and one physical NIC. As shown, VM 210 is
connected to the forwarding element 205 through VNIC 225 and port
260. PNIC 220 is connected to the forwarding element 205 through
the uplink 250 and port 235 of port group 230. Utilizing the
forwarding element 205 to exchange packets between VM 210 and PNIC
220 create extra processing overhead.
[0037] Some embodiment, dynamically identify the conditions where
the forwarding element can be bypassed in the connection between a
VM and a PNIC. These conditions include that only two ports of the
switch are connected: a port connected to a VM (through a VNIC) and
a port connected to an uplink. Another condition is that port
mirroring/packet forwarding is not enabled for the switch. When
port mirroring is enabled for a forwarding element, a copy of each
packet passing through a port is sent to another port (a port
different than the port PNIC is connected to) to monitor the packet
traffic (e.g., to detect intrusion, to do performance monitoring,
etc.). Under the above-mentioned conditions, the VM sends and
receives packets through only one PNIC and there is no need for
port mirroring. As shown in FIG. 2, VM 210 and PNIC 220 are the
only entities connected to the forwarding element's ports.
[0038] FIG. 3 conceptually illustrates the VM of FIG. 2 after the
forwarding element is bypassed in some embodiments of the
invention. As shown, there are no forwarding elements in the path
between VM 210 and PNIC 220 and a direct path (as conceptually
shown by the line 305) is provided between the VNIC 225 and the
uplink 250 to exchange packets between the VM 210 and the PNIC 220.
The decision to bypass the forwarding element is dynamically made
during runtime when a set of conditions is met. Once the use of a
forwarding element is required again, the packet exchange between
the VM is the PNIC is once again performed through the forwarding
element 205.
[0039] Different embodiments provide different mechanisms for
bypassing the forwarding element. Since the forwarding element 205
is implemented in software, some embodiments provide a fast path
through the forwarding element software to bypass the functionality
of the forwarding element. The following pseudo code illustrates
bypassing of the forwarding element functionality in some
embodiments of the invention.
TABLE-US-00001 if all conditions for bypassing the forwarding
element are satisfied fastpath = TRUE else fastpath = FALSE /***
Perform forwarding element functionalities ***/ switching ( ) if
fastpath then return else { /* perform forwarding element
functionalities */ }
[0040] In some embodiments, each time a VNIC is connected to a
port, a callback is generated to the virtualization software.
Similarly, when a PNIC is connected to a port through an uplink, a
callback is generated to the virtualization software. The
virtualization software is therefore able to determine the number
of VNICs and PNICs that are connected to a forwarding element at
each time.
[0041] Some embodiments bypass the forwarding element by providing
a direct software link between the uplink and the VNIC driver for
the duration that the forwarding element is bypassed. In either
case, only the forwarding element is bypassed in order to eliminate
unnecessary processing for the forwarding element while the
virtualization software is still aware of the interactions between
the VM and other components of the system and is capable of
dynamically connecting the VM to the PNIC through the forwarding
element once the need arises for the use of the forwarding element
during the runtime.
[0042] From a security perspective, bypassing the forwarding
element in combination with a vulnerability in the
physical/upstream infrastructure can allow the VM to receive
packets from any other VMs. For a proper defense in depth
implementation, some embodiments ensure that the VM port has proper
security credentials before allowing bypass. As an additional
condition for allowing the bypassing of the forwarding element,
these embodiments determine whether the port that connects the VM
to the forwarding element can send packets to arbitrary media
access control (MAC) addresses and can receive packets with
arbitrary destination MAC addresses (promiscuous mode). Such a
condition is not very limiting as the forwarding element bypass is
targeted towards high packet rate applications and many such
applications are gateway/edge applications and are able to receive
and send arbitrary MAC address packets.
[0043] FIGS. 4A and 4B conceptually illustrate a process 400 for
determining whether a forwarding element can be bypassed in the
path between a VM and a physical NIC in some embodiments of the
invention. As shown, the process initially uses (at 405) a
forwarding element for exchanging packets between the VM and the
physical NIC. The process then determines (at 410) whether only two
ports of the forwarding elements are used, one port connecting to
the VM (e.g., through a VNIC) and one port connecting to the
physical NIC (e.g., through an uplink). If not, the process
proceeds (e.g., after some predetermined delay) to 405, which was
described above. For instance, more than two ports are used when
the VM is required to be connected to more than one physical NIC or
any other VMs are connected to the forwarding element.
[0044] Otherwise, the process determines (at 420) whether port
mirroring is enabled on the forwarding element. If yes, the process
proceeds (e.g., after some predetermined delay) to 405, which was
described above. Otherwise, the process determines (at 425) whether
there are any other conditions that require the use of the
forwarding element for exchanging packets between the VM and the
PNIC. For instance, some embodiments determine whether the port
connected to the VM has proper security credentials before allowing
the bypass (e.g., whether the port can send arbitrary MAC address
packets and can receive arbitrary MAC address packets, i.e., to
operate in promiscuous mode).
[0045] Another condition for bypassing a forwarding element is the
network virtualization (e.g., tunnels for overlay networks such as
Virtual eXtensible LAN (VXLAN), Generic Network Virtualization
Encapsulation (GENEVE), Network Virtualization using Generic
Routing Encapsulation (NVGRE), and stateless transport tunneling
(STT)) is not performed by the forwarding element. In other words,
the forwarding element is not a part of a software-defined network.
In some embodiments, the forwarding element encapsulates the
outgoing packets and decapsulates the incoming packets. In such
cases, the forwarding element cannot be bypassed due to the
required encapsulation/decapsulation functionality of the
forwarding element. In some embodiments, the encapsulation and
decapsulation of packets for such tunnels is done outside of a
forwarding element.
[0046] Therefore, the condition that the forwarding element does
not encapsulate and decapsulate packets is satisfied either when
the encapsulation and decapsulation of packets is done outside the
forwarding element or the forwarding element is capable of
encapsulating and decapsulating the packets but such encapsulation
and decapsulation is not enabled (e.g., the overlay network tunnels
are not used by the VM that is connected to the forwarding
element). If there are any other conditions that require the use of
the forwarding element, the process proceeds (e.g., after some
predetermined delay) to 405, which was described above. Otherwise,
the process bypasses (at 430) the forwarding element for exchanging
packets between the VM and the physical NIC.
[0047] The process then dynamically determines whether the
conditions have changed and the forwarding element can no longer be
bypassed. The process determines (at 435) whether more than two
ports of the forwarding element are being used. For instance, VM is
required to be connected to more than one physical NIC or any other
VMs are connected to the forwarding element. If yes, the process
proceeds back to 405 to use the forwarding element for exchanging
the packets between the VM and the physical NIC.
[0048] Otherwise, the process determines (at 445) whether port
mirroring is enabled on the forwarding element. If yes, the process
proceeds back to 405 to use the forwarding element for exchanging
the packets between the VM and the physical NIC. Otherwise, the
process determines (at 450) whether any other conditions (as
described above by reference to operation 425) exist that require
the use of forwarding element for exchanging packets between the VM
and the PNIC. If yes, the process proceeds back to 405 to use the
forwarding element for exchanging the packets between the VM and
the physical NIC. Otherwise, the process proceeds (e.g., after some
predetermined delay) back to 435 and continues to bypass the
forwarding element for exchanging packets between the VM and the
physical NIC.
[0049] The decision for whether or not to perform the optimization
of bypassing the forwarding element is taken based on local data
available on the particular host that is implementing the
optimization. The decision is made based on the ports connected to
forwarding element on the particular host and types of features
enabled for the connected ports. For instance, the decision to
determine how many ports are connected to the forwarding element is
based on whether or not a VM on the particular hot is powered on.
The VMs that are powered off are considered as not connected to the
forwarding element. On the other hand, when a link is down for a
PNIC, the PNIC is still considered as connected to the forwarding
element. The decision whether port mirroring is enabled is based on
whether the port mirroring is enabled for the ports connected to
the forwarding element on the particular host. Therefore, even if
the forwarding element is an LFE (which is a virtual distributed
switch), local information are utilized to determined how many
ports of the forwarding element is currently connected in order to
make the decision to bypass or use the forwarding element.
[0050] B. Bypassing the Forwarding Element in SR-IOV
[0051] Single Root input-output (I/O) Virtualization (SR-IOV) is a
specification that allows a single Peripheral Component
Interconnect Express (PCIe) physical device under a single root
port to appear to be multiple separate physical devices to the
virtualization software or the guest operating system. SR-IOV uses
physical functions (PFs) and virtual functions (VFs) to manage
global functions for the SR-IOV devices.
[0052] PFs are full PCIe functions that include the SR-My extended
capability, which is used to configure and manage the SR-IOV
functionality. It is possible to configure or control PCIe devices
using PFs, and the PF has full ability to move data in and out of
the device. VFs are lightweight PCIe functions that contain all the
resources necessary for data movement but have a minimized set of
configuration resources. SR-IOV enabled PCIe devices present
multiple instances of themselves to the guest operating system
instance and the host virtualization software.
[0053] FIG. 5 conceptually illustrates SR-IOV virtualization on a
host in some embodiments of the invention. The VMs of other tenants
(if any) are not shown for simplicity. As shown, the SR-My capable
PNIC 505 includes several VFs 510 and one PF 515. VMs 520 have a
direct path to VFs 510. On the other hand, PF 515 is connected to
several VMs 525-530 through uplink 540, forwarding element 535, and
VNICs 545.
[0054] The instantiated VFs 510 can be configured such that they
are directly assigned to VMs and the guest operating system's VF
driver (not shown) takes possession of the VF. For instance, each
VF can create a direct path from a VM to the physical NIC. While
such configuration delivers near native network performance to the
VM, the data path bypasses the virtualization software/network
stack (i.e., the VFs are pass-through devices). Hence such VFs in
those VMs are unable to benefit from an overlay network based
multi-tenant environment.
[0055] However, some or all VMs on a host may not be capable of
using an SR-IOV VF in some embodiments. These VMs may need some
virtualization features that cannot be provided if the VM bypasses
the virtualization software/network stack and is directly connected
to a VF. For instance, a VM may require memory overcommit, which is
a feature provided by virtualization software that allows a VM to
use more memory space than the physical host has available. As an
example, on a host with 10 GB of physical memory, the
virtualization software may allow 5 VMs, each with 4 GB of
allocated memory space to run a host with only 10 GB of physical
memory. Some embodiments allow such VMs to still connect to a VF
without bypassing the virtualization software stack.
[0056] FIG. 6 conceptually illustrates SR-IOV virtualization on a
host in some embodiments of the invention where VMs that cannot
bypass virtualization software stack are connected to a single
SRI-OV enabled PNIC. VMs 605-610 are VMs that require the services
of software virtualization 215. For instance, the VMs may require
memory overcommit. As shown, each of the k VMs 605-610 is
associated with one VNIC 630-635. Each VNIC 630-635 is connected to
a port 680-685 of a single forwarding element 690. The forwarding
element 690 is connected to PF 515 of the PNIC 625 through uplink
540. VMs 605-610 are VMs of one tenant. VMs of other tenants (if
any) are on separate logical networks and are not shown.
[0057] Some of VFs on PNIC 625 may be utilized by the
virtualization software 215 to connect to kernel VNICs , referred
to as VMKNICs (not shown). If the PNIC 625 has n available VFs
650-655 and n>=k, then the virtualization software 215 assigns k
VFs from the PNIC 625 and treats each of them as a new PNIC. The
virtualization software also creates k new forwarding elements and
attaches one VNIC and one VF to each forwarding element. The VNICs
are also detached from the original FE.
[0058] FIG. 7 conceptually illustrates SR-IOV virtualization of
FIG. 6 where each VM is connected to a different VF through a
separate forwarding element. As shown, k VMs 605-610 that were
previously (as shown in FIG. 6) connected to a single forwarding
element 690 are now connected to k separate forwarding elements
715-720 through their associated VNICs 630-635. Each forwarding
element 715-720 is connected to one of the k VFs 650-652 of the
RS-IOV enabled PNIC 625. The process of creation of the forwarding
elements 715-720, connecting VNICs 630-635 to the forwarding
elements, and connecting the forwarding elements to VFs 650-652 is
completely transparent to the VNICs and VMs in some
embodiments.
[0059] Now there is a single uplink and a single VM connected to
each of the forwarding elements 715-720 and whenever a set of
conditions (as described below) is satisfied, each of the
forwarding elements 715-720 can be bypassed. When the set of
conditions fails, then all forwarding elements 715-720 are deleted
and the VNICs are connected back to the forwarding element 690
(shown in FIG. 6), which frees all VFs 650-652.
[0060] Some embodiment, dynamically identify the condition where a
forwarding element 715-720 can be bypassed in the connection
between a VNICs 630-635 and a VFs 650-652. Since each forwarding
element 715-720 is connected to only one of the VNICs 630-635 and
one of the VFs 650-652, the forwarding elements satisfy the
condition that only two ports to be used on the forwarding element.
Another condition for bypassing the forwarding element is that port
mirroring is not enabled on the forwarding element.
[0061] As another condition, some embodiments determine (as
described above by reference to operation 425) whether the port
connected to the VNIC has proper security credentials before
allowing the bypass. Yet another condition for bypassing a
forwarding element is the network virtualization (e.g., tunnels for
overlay networks such as VXLAN, GENEVE, NVGRE, and STT) is not
performed by the forwarding element. In some embodiments, the
forwarding element encapsulates the outgoing packets and
decapsulates the incoming packets. In such cases, the forwarding
element cannot be bypassed due to the required
encapsulation/decapsulation functionality of the forwarding
element. In some embodiments, the encapsulation and decapsulation
of packets for such tunnels is done outside of a forwarding
element.
[0062] Therefore, the condition that the forwarding element does
not encapsulate and decapsulate packets is satisfied either when
the encapsulation and decapsulation of packets is done outside the
forwarding element or the forwarding element is capable of
encapsulating and decapsulating the packets but such encapsulation
and decapsulation is not enabled (e.g., the overlay network tunnels
are not used by the VM that is connected to the forwarding
element).
[0063] Another condition that prevents bypassing of the forwarding
elements is when n+1 VMs are powered on and/or moved to the host,
i.e., when the number of VMs becomes larger than the number of
available VFs on the PNIC. For instance, as a new VM is powered on
or a VM is moved (from another host) to the host, the networking
layer in the host creates a new forwarding element for the VM and
assigns one of the n VFs in the SR-My PNIC to the VM.
Alternatively, an administrator can enable a previously disabled
VNIC to connect the VNIC to one of the VFs through a forwarding
element. Eventually, the number of VMs on the host may become
larger than the number of available VFs, which prevents bypassing
of the forwarding elements.
[0064] FIG. 8 conceptually illustrates SR-IOV virtualization on a
host in some embodiments of the invention where a VM that cannot
bypass virtualization software stack bypasses the forwarding
element and connects to a VF through a VNIC. As shown, the
forwarding element 615 is bypassed for exchanging packets between
VM 605 and VF 650. As conceptually shown by line 805, there are no
forwarding elements in the path between VNIC 630 and VF 650. The
path between the VM 605, VNIC 630, and VF 650, still goes through
the virtualization software stack (as opposed to the paths between
VMs 520 and VFs 510 in FIG. 5 that bypass the virtualization
software stack).
[0065] On the other hand, in the example of FIG. 7, the forwarding
element 620 does not satisfy all conditions for bypassing (e.g.,
port mirroring may be enabled on the forwarding element or
forwarding element may be used to encapsulate/decapsulate packets
for an overlay network). Forwarding element 620, is therefore, not
bypassed.
[0066] The decision whether or not to bypass a forwarding element
to connect a VM and the corresponding VNIC directly to a VF is
dynamically made in some embodiments. FIG. 9 conceptually
illustrates a process 900 for determining whether each VMs on a
host can be connected to a VF of an SR-IOV capable PNIC in some
embodiments of the invention. As shown, the process connects (at
905) all VMs' VNICs through a single forwarding element to a PF of
an SR-IOV capable PNIC (e.g., as shown in FIG. 6).
[0067] The process then determines (at 910) whether the number of
available VFs on the PNIC is the same or larger than the number of
VMs. If not, the process proceeds (e.g., after a predetermined
delay) to 905, which was described above. Otherwise, the process
creates (at 915) one forwarding element for each VM. The process
then connects (at 920) each forwarding element to (i) the VNIC of
the corresponding VM and (ii) one of the PNIC' s available VFs
(e.g., as shown in FIG. 7)
[0068] As long as a set of conditions is satisfied for a forwarding
element, the process bypasses (at 925) the forwarding element and
connects the VM' s VNIC to the associated VF (e.g., as shown in
FIG. 8). Details of operation 925 are further described by
reference to FIG. 10, below. The process then determines (at 930)
whether the number of available VFs on the PNIC is the same or
larger than the number of VMs. If not, the process proceeds (e.g.,
after a predetermined delay) to 905 to connect all VNICs to a
single forwarding element. Otherwise, the process proceeds (e.g.,
after a predetermined delay) to 920, which was described above.
[0069] FIG. 10 conceptually illustrates a process 1000 for
determining whether a forwarding element can be bypassed in the
path between a VM and a VF of an SR-IOV enabled PNIC in some
embodiments of the invention. As shown, the process initially uses
(at 1005) a forwarding element for exchanging packets between the
VM (and the VM's corresponding VNIC) and a VF of an SR-IOV enabled
physical NIC. The process then determines (at 1010) whether port
mirroring is enabled on the forwarding element. If yes, the process
proceeds (e.g., after some predetermined delay) to 805, which was
described above. Otherwise, the process determines (at 1020)
whether there are any other conditions that require the use of the
forwarding element for exchanging packets between the VM and the
PNIC. For instance, some embodiments determine whether the port
connected to the VM has proper security credentials before allowing
the bypass (e.g., whether the port can send arbitrary MAC address
packets and can receive arbitrary MAC address packets, i.e., to
operate in promiscuous mode).
[0070] Another condition for bypassing a forwarding element is the
network virtualization is not performed by the forwarding element
(as described above by reference to operation 425 in FIG. 4). In
other words, the forwarding element is not a part of a
software-defined network. If there are any other conditions that
require the use of the forwarding element, the process proceeds
(e.g., after some predetermined delay) to 1005, which was described
above. Otherwise, the process bypasses (at 1025) the forwarding
element for exchanging packets between the VM and the VF (e.g., as
shown for VM 605 in FIG. 8).
[0071] The process then dynamically determines whether the
conditions have changed and the forwarding element can no longer be
bypassed. The process determines (at 1030) whether port mirroring
is enabled on the forwarding element. If yes, the process proceeds
back to 1005 to use the forwarding element for exchanging the
packets between the VM and the physical NIC. Otherwise, the process
determines (at 1035) whether any other conditions (as described
above by reference to operation 425) exist that require the use of
forwarding element for exchanging packets between the VM and the
PNIC. If yes, the process proceeds back to 1005 to use the
forwarding element for exchanging the packets between the VM and
the physical NIC. Otherwise, the process proceeds (e.g., after some
predetermined delay) back to 1030 and continues to bypass the
forwarding element for exchanging packets between the VM and the
physical NIC.
[0072] In some embodiments, VM 605 can have more than one VNIC (not
shown). Each of the VM' s VNICs can be connected to a separate
forwarding element. Similar to the example of FIG. 8, a VM with
multiple VNICs can bypass any or all of the forwarding elements
connected to it as long as all conditions (as described above) for
bypassing the forwarding element are satisfied.
[0073] SR-IOV PNICs have built in switches. As long as all VMs are
assigned separate VFs, the SR-IOV PNIC can be relied to do the
switching. However, this path is more expensive than doing the
switching with a forwarding element, but the optimization is more
targeted towards packets transiting through the SR-My PNIC.
[0074] As discussed by reference to FIGS. 3 and 8 above, a
forwarding element is dynamically bypassed under certain
conditions. Different embodiments provide different mechanisms for
bypassing the forwarding element. Some embodiments provide a fast
path through the forwarding element software to bypass the
functionality of the forwarding element. Other embodiments bypass
the forwarding element by providing a direct software link between
the uplink and the VNIC driver for the duration that the forwarding
element is bypassed.
[0075] II. Selective use of Polling Instead of Interrupt Processing
for High Packet Rate Applications
[0076] Some embodiments identify applications that consistently
have high packet rates. These embodiments provide a tradeoff
between the processing resources and higher packet rates. These
embodiments modify virtual device processing to occur in polling
mode rather then interrupt (or sys-call) driven mode. Streamlining
virtual device processing provides a two-fold advantage. First,
packet processing does not incur any latency. Second, the virtual
backend, virtual machine monitor, guest kernel, and guest device
driver for the virtual network device do not have to execute
interrupt coalescing and interrupt processing code. The processing
overhead is reduced by 1%-2%, increasing packet processing by a
similar amount. Some embodiments turn on/off the polling mode when
a VNIC is initialized (e.g., at the time of VM boot or VNIC reset).
In other embodiments, the polling mode is adaptively turned on or
off during the runtime. In these embodiments, polling is turned on
when packet rate is high and turns off polling when the packet rate
is low.
[0077] Interrupt coalescing is a technique to hold back events that
generate interrupts until a certain amount of time passes or a
certain about of data to process is collected. When a VM generates
a packet to send out (a transmit packet), the VNIC deriver
generates an interrupt (e.g., by performing a call) to the
virtualization software to inform the virtualization software of
the pending transmit packet. In some embodiments, the VNIC driver
implements interrupt coalescing by keeping the transmit packets in
a buffer until a predetermined number of transmit packets are
received from the VM or a predetermined amount of time since the
last interrupt by the VNIC driver to the virtualization software
has elapsed. In some embodiments, whichever of these two conditions
occur, the VNIC driver interrupts the virtualization software.
[0078] FIG. 11 conceptually illustrates a process 1100 for
dynamically determining whether to use polling or interrupts to
send transmit packets from each of a tenant's VMs to the
virtualization software in some embodiments of the invention. In
the following discussions, a transmit packet refers to a packet
generated by the VM for transmission to entities outside the VM. As
shown, the process sets (at 1105) the current VM to the tenant's
first VM.
[0079] The process then determines (at 1110) whether the rate of
packets received at the VNIC from the VM is higher than a
predetermined threshold. If yes, the process determines (at 1120)
that polling between the virtualization software and the current
VM' s VNIC shall be used to indicate the availability of transmit
packets received at the VNIC from the VM. The process then proceeds
to 1125, which is described below.
[0080] Otherwise, the process determines (at 1115) that interrupts
shall be used by the VM's VNIC to inform the virtualization
software of the availability of transmit packets received at the
VNIC from the VM. As described below, some embodiments perform
mechanisms such as interrupt coalescing to interrupt the
virtualization software. The process then determines (at 1125)
whether all VMs of the tenant are examined. If yes, the process
proceeds to 1110, which was described above. Otherwise, the process
sets (at 1130) the current VM to the tenant's next VM. The process
then proceeds to 1110, which was described above.
[0081] FIG. 12 conceptually illustrates a process 1200 for
performing interrupt coalescing in some embodiments of the
invention. As shown, the process determines (at 1205) whether
packets are received from the VM. If not, the process returns
(e.g., after a predetermined delay) to 1205). Otherwise, the
process determines (at 1210) whether a predetermined number of
packets is received from the VM. If yes, the process proceeds to
1220, which is described below.
[0082] Otherwise, the process determines (at 1215) whether a
predetermined amount of time has elapsed since the first packet
currently in the buffer has arrived. If no, the process proceeds to
1225, which is described below. Otherwise, the process generates
(at 1220) an interrupt to the virtualization software and provides
the location and the number of packets that the virtualization
software (e.g., the forwarding element of the virtualization
software) has to pick up from the buffer to transmit. In some
embodiments, the interrupt is generated by a calling mechanism to
virtualization software. For instance a hypercall is made from the
VNIC driver to the virtualization software to generate a software
trap to activate the transmit processing. The process then proceeds
to 1205, which was described above. The process saves (at 1225) the
transmit packet in a buffer to inform the virtualization software
at a later time. The process then proceeds to 1205, which was
described above. Generation of an interrupt to virtualization
software causes the virtualization software to pick up the packets
and reset the number of packets in the buffer to zero.
[0083] FIG. 13 conceptually illustrates a process 1300 performed by
the VNIC when the virtualization software performs polling to
determine the availability of VM transmit packets in some
embodiments of the invention. As shown, the process initializes (at
1305) a buffer for saving VM transmit packets for pick up by the
virtualization software.
[0084] The process then determines (at 1310) whether a transmit
packet is received from the VM. If not, the process proceeds (e.g.,
after a predetermined time) to 1310. Otherwise, the process saves
(at 1315) the transmit packet in a buffer to be picked up by the
virtualization software at a later time. The process then updates
(at 1320) the number of packets to pick up by the virtualization
software. The process then proceeds to 1310, which was described
above.
[0085] FIG. 14 conceptually illustrates a process 1400 performed by
the virtualization software in some embodiments to poll a VNIC to
determine whether transmit packets are available from the VM. As
shown, the process starts (at 1405) a timer to perform the next
poll. The process then determines (at 1410) whether it is time to
poll the VNIC for the availability of a VM transmit packet. For
instance, the process determines whether the timer started at 1405
has expired.
[0086] If not, the process returns (at after a predetermined time
delay) to 1410. Otherwise, the process determines (at 1415) whether
any VM transmit packets are available in VNIC buffer to pick up
(e.g., as set by process 1300 in operation 1315). If not, the
process proceeds to 1430, which is described below.
[0087] Otherwise, the process picks up (at 1420) the transmit
packets from the buffer. The process then initializes (at 1425) the
buffer to be filled up by the VNIC. For instance, the process sets
the number of packets in the buffer to zero. The process then
starts (at 1430) a timer for performing the next poll. The process
then proceeds to 1410, which was described above.
[0088] III. Electronic System
[0089] Many of the above-described features and applications are
implemented as software processes that are specified as a set of
instructions recorded on a computer readable storage medium (also
referred to as computer readable medium). When these instructions
are executed by one or more processing unit(s) (e.g., one or more
processors, cores of processors, or other processing units), they
cause the processing unit(s) to perform the actions indicated in
the instructions. Examples of computer readable media include, but
are not limited to, CD-ROMs, flash drives, RAM chips, hard drives,
EPROMs, etc. The computer readable media does not include carrier
waves and electronic signals passing wirelessly or over wired
connections.
[0090] In this specification, the term "software" is meant to
include firmware residing in read-only memory or applications
stored in magnetic storage, which can be read into memory for
processing by a processor. Also, in some embodiments, multiple
software inventions can be implemented as sub-parts of a larger
program while remaining distinct software inventions. In some
embodiments, multiple software inventions can also be implemented
as separate programs. Finally, any combination of separate programs
that together implement a software invention described here is
within the scope of the invention. In some embodiments, the
software programs, when installed to operate on one or more
electronic systems, define one or more specific machine
implementations that execute and perform the operations of the
software programs.
[0091] FIG. 15 conceptually illustrates an electronic system 1500
with which some embodiments of the invention are implemented. The
electronic system 1500 can be used to execute any of the control,
virtualization, compute manager, network manager, or operating
system applications described above. The electronic system 1500 may
be a computer (e.g., a desktop computer, personal computer, tablet
computer, server computer, mainframe, a blade computer etc.),
phone, PDA, or any other sort of electronic device. Such an
electronic system includes various types of computer readable media
and interfaces for various other types of computer readable media.
Electronic system 1500 includes a bus 1505, processing unit(s)
1510, a system memory 1520, a read-only memory (ROM) 1530, a
permanent storage device 1535, input devices 1540, and output
devices 1545.
[0092] The bus 1505 collectively represents all system, peripheral,
and chipset buses that communicatively connect the numerous
internal devices of the electronic system 1500. For instance, the
bus 1505 communicatively connects the processing unit(s) 1510 with
the read-only memory 1530, the system memory 1520, and the
permanent storage device 1535.
[0093] From these various memory units, the processing unit(s) 1510
retrieve instructions to execute and data to process in order to
execute the processes of the invention. The processing unit(s) may
be a single processor or a multi-core processor in different
embodiments.
[0094] The read-only-memory 1530 stores static data and
instructions that are needed by the processing unit(s) 1510 and
other modules of the electronic system. The permanent storage
device 1535, on the other hand, is a read-and-write memory device.
This device is a non-volatile memory unit that stores instructions
and data even when the electronic system 1500 is off. Some
embodiments of the invention use a mass-storage device (such as a
magnetic or optical disk and its corresponding disk drive) as the
permanent storage device 1535.
[0095] Other embodiments use a removable storage device (such as a
floppy disk, flash drive, etc.) as the permanent storage device.
Like the permanent storage device 1535, the system memory 1520 is a
read-and-write memory device. However, unlike storage device 1535,
the system memory is a volatile read-and-write memory, such a
random access memory. The system memory stores some of the
instructions and data that the processor needs at runtime. In some
embodiments, the invention's processes are stored in the system
memory 1520, the permanent storage device 1535, and/or the
read-only memory 1530. From these various memory units, the
processing unit(s) 1510 retrieve instructions to execute and data
to process in order to execute the processes of some
embodiments.
[0096] The bus 1505 also connects to the input and output devices
1540 and 1545. The input devices enable the user to communicate
information and select commands to the electronic system. The input
devices 1540 include alphanumeric keyboards and pointing devices
(also called "cursor control devices"). The output devices 1545
display images generated by the electronic system. The output
devices include printers and display devices, such as cathode ray
tubes (CRT) or liquid crystal displays (LCD). Some embodiments
include devices such as a touchscreen that function as both input
and output devices.
[0097] Finally, as shown in FIG. 15, bus 1505 also couples
electronic system 1500 to a network 1525 through a network adapter
(not shown). In this manner, the computer can be a part of a
network of computers (such as a local area network ("LAN"), a wide
area network ("WAN"), or an Intranet, or a network of networks,
such as the Internet. Any or all components of electronic system
1500 may be used in conjunction with the invention.
[0098] Some embodiments include electronic components, such as
microprocessors, storage and memory that store computer program
instructions in a machine-readable or computer-readable medium
(alternatively referred to as computer-readable storage media,
machine-readable media, or machine-readable storage media). Some
examples of such computer-readable media include RAM, ROM,
read-only compact discs (CD-ROM), recordable compact discs (CD-R),
rewritable compact discs (CD-RW), read-only digital versatile discs
(e.g., DVD-ROM, dual-layer DVD-ROM), a variety of
recordable/rewritable DVDs (e.g., DVD-RAM, DVD-RW, DVD+RW, etc.),
flash memory (e.g., SD cards, mini-SD cards, micro-SD cards, etc.),
magnetic and/or solid state hard drives, read-only and recordable
Blu-Ray.RTM. discs, ultra density optical discs, any other optical
or magnetic media, and floppy disks. The computer-readable media
may store a computer program that is executable by at least one
processing unit and includes sets of instructions for performing
various operations. Examples of computer programs or computer code
include machine code, such as is produced by a compiler, and files
including higher-level code that are executed by a computer, an
electronic component, or a microprocessor using an interpreter.
[0099] While the above discussion primarily refers to
microprocessor or multi-core processors that execute software, some
embodiments are performed by one or more integrated circuits, such
as application specific integrated circuits (ASICs) or field
programmable gate arrays (FPGAs). In some embodiments, such
integrated circuits execute instructions that are stored on the
circuit itself.
[0100] As used in this specification, the terms "computer",
"server", "processor", and "memory" all refer to electronic or
other technological devices. These terms exclude people or groups
of people. For the purposes of the specification, the terms display
or displaying means displaying on an electronic device. As used in
this specification, the terms "computer readable medium," "computer
readable media," and "machine readable medium" are entirely
restricted to tangible, physical objects that store information in
a form that is readable by a computer. These terms exclude any
wireless signals, wired download signals, and any other ephemeral
or transitory signals.
[0101] While the invention has been described with reference to
numerous specific details, one of ordinary skill in the art will
recognize that the invention can be embodied in other specific
forms without departing from the spirit of the invention. In
addition, a number of the figures including FIGS. 4A-4B and 9-14
conceptually illustrate processes. The specific operations of these
processes may not be performed in the exact order shown and
described. The specific operations may not be performed in one
continuous series of operations, and different specific operations
may be performed in different embodiments. Furthermore, the process
could be implemented using several sub-processes, or as part of a
larger macro process.
[0102] This specification refers throughout to computational and
network environments that include virtual machines (VMs). However,
virtual machines are merely one example of data compute nodes
(DCNs) or data compute end nodes, also referred to as addressable
nodes. DCNs may include non-virtualized physical hosts, virtual
machines, containers that run on top of a host operating system
without the need for a hypervisor or separate operating system, and
hypervisor kernel network interface modules.
[0103] VMs, in some embodiments, operate with their own guest
operating systems on a host using resources of the host virtualized
by virtualization software (e.g., a hypervisor, virtual machine
monitor, etc.). The tenant (i.e., the owner of the VM) can choose
which applications to operate on top of the guest operating system.
Some containers, on the other hand, are constructs that run on top
of a host operating system without the need for a hypervisor or
separate guest operating system. In some embodiments, the host
operating system uses name spaces to isolate the containers from
each other and therefore provides operating-system level
segregation of the different groups of applications that operate
within different containers. This segregation is akin to the VM
segregation that is offered in hypervisor-virtualized environments
that virtualize system hardware, and thus can be viewed as a form
of virtualization that isolates different groups of applications
that operate in different containers. Such containers are more
lightweight than VMs.
[0104] Hypervisor kernel network interface module, in some
embodiments, is a non-VM DCN that includes a network stack with a
hypervisor kernel network interface and receive/transmit threads.
One example of a hypervisor kernel network interface module is the
vmknic module that is part of the ESXi.TM. hypervisor of VMware,
Inc.
[0105] One of ordinary skill in the art will recognize that while
the specification refers to VMs, the examples given could be any
type of DCNs, including physical hosts, VMs, non-VM containers, and
hypervisor kernel network interface modules. In fact, the example
networks could include combinations of different types of DCNs in
some embodiments.
[0106] In view of the foregoing, one of ordinary skill in the art
would understand that the invention is not to be limited by the
foregoing illustrative details, but rather is to be defined by the
appended claims.
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